According to the recent trend of lighting technology, an LED (Light Emitting Diode) has been employed as a light source.
A high-brightness LED is differentiated from other light sources in terms of various aspects such as energy consumption, lifetime, and light quality.
However, a lighting apparatus using LEDs as a light source may require additional circuits due to the characteristic of the LEDs which are driven by a constant current.
Examples of devices which have been developed to solve the above-described problem may include an AC direct-type lighting apparatus.
In general, the AC direct-type LED lighting apparatus is designed to rectify a commercial voltage and drive LEDs using the rectified voltage having a ripple which is two times larger than the commercial frequency. A voltage obtained by full-wave rectifying an AC voltage based on the commercial voltage is referred to as a rectified voltage.
Since the above-described AC direct-type LED lighting apparatus directly uses the rectified voltage as an input voltage without using an inductor and capacitor, the AC direct-type LED lighting apparatus has a favorable power factor.
The LED lighting apparatus includes a large number of LEDs connected in series, and the LEDs may be divided into a plurality of LED groups. The plurality of LED groups may be sequentially turned on/off according to the rise/fall of a rectified voltage having a ripple.
The LED lighting apparatus which is operated by the rectified voltage may additionally include a peripheral circuit for dimming control or operation control. That is, a sensor board which includes a sensor for sensing luminance or human body and performs dimming control or switching control, or a communication device which communicates with the outside may be configured as a peripheral circuit of the LED lighting apparatus.
In this case, the LED lighting apparatus needs to include a separate power supply circuit to supply an operating voltage to the peripheral circuit such as a sensor board or communication device.
When the additional power supply circuit is mounted to independently supply an operating voltage to the peripheral circuit, the configuration of the LED lighting apparatus may become complex.
Furthermore, as power is independently supplied to the additional parts as well as the LEDs of the LED lighting apparatus, the entire power consumption may be increased, and the power efficiency may be degraded.